As used, strings stretched over a racket are damaged on surface by frictions between strings or with balls.
As damaged on surface, longitudinal and transverse strings engage each other at intersections and make notches.
Notched strings are twisted and degraded in elasticity, bounce, etc., while causing more vibrations at the moment of hitting a ball.
Then, technique for improving strings in elasticity, bounce, etc., is desired.
For example, resin coating technique for improving ball control of a racket is known (see International Publication No. WO97/40228).
This technique makes strings adhere to each other so as to fix longitudinal and transverse strings at intersections, with the use of a coating agent of solution which consists of 1 to 50% recent resin or fossil resin in low boiling point organic solvent, to prevent strings from twisting for better ball control.
However, depending on their skills, some users feel uncomfortable when hitting a ball with such a racket that longitudinal and transverse strings are fixed at intersections.
Then, the object of the present invention is providing means for preventing strings from being damaged on surface, making them be hard to twist and improving them in elasticity, bounce, etc., without the uncomfortable touch at the moment of hitting a ball